A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a wireless communication channel or link with a number of client devices or stations (STAs). Each AP, which may correspond to a Basic Service Set (BSS), periodically broadcasts beacon frames to enable any STAs within wireless range of the AP to establish and/or maintain a communication link with the WLAN (also known as the Wi-Fi network). The beacon frames, which may include a traffic indication map (TIM) and/or a delivery traffic indication message (DTIM) indicating whether the AP has queued downlink data for the STAs, are typically broadcast according to a target beacon transmission time (TBTT) schedule.
The IEEE 802.11d standards allow an AP to include an Information Element (IE) in the beacon frames that includes country code information of the AP. The country code information may include a country code indicating a country, region, or domain where the AP is located, and may also include a list of authorized channels, transmit power levels, and other restrictions (e.g., imposed by a government or regulatory agency). For example, countries typically apply their own regulations to both the authorized channels, allowed users, and maximum power levels for various wireless frequency ranges. These regulations may vary between countries. For example, while Japan may currently allow Wi-Fi devices to operate on a particular channel, the United States may currently not allow Wi-Fi devices to operate on the particular channel. A station (STA) receiving these beacon frames may extract the country code information to determine in which country or domain the AP is located, and then use only those acceptable channels and corresponding transmit power levels associated with that country.
Thus, for a STA to comply with such regulations, the country code information provided in the beacon frames must be accurate. Unfortunately, when a particular AP is malfunctioning or is being maliciously operated (hereinafter referred to as a “rogue” AP), the AP may provide incorrect country code information to the STA, which in turn may cause the STA to run afoul of regulations specified by the country in which the STA is currently located (e.g., by transmitting on channels that are not authorized by the country and/or by transmitting at power levels greater than the power limits allowed by the country).
In addition, when the STA is near a border between two countries, the STA may receive beacon frames from groups of APs that are located in different countries, where a first group of APs may broadcast country code information pertaining to a first country and a second group of APs may broadcast country code information pertaining to a second country. In this situation, it is desirable for the STA to select the correct country code information broadcast from the different groups of APs so that the STA complies with regulations imposed by the country in which the STA is located.